Can carotid ultrasound predict plaque histopathology?

Abstract

Aim: European and North American studies have confirmed the benefits of carotid endarterectomy for patients with symptomatic carotid artery stenoses >70%. However, the management of asymptomatic patients and those with lesser degrees of stenosis is less certain. Several studies have suggested that, for these subgroups, the targeting of potentially unstable plaques, may help to identify those most at risk of cerebrovascular accidents and thus most likely to benefit from surgery. The aim of this study was to correlate the ultrasound features of carotid artery stenosis with the histopathological findings of the carotid endarterectomy specimens in order to identify features which will allow preoperative identification of clinically unstable plaques.

Methods: Sixty consecutive patients with symptomatic, critical carotid stenosis were prospectively studied. Plaques were classified preoperatively into one of five types based on their echogenicity and were also assessed for irregularity and ulceration. These findings were then compared with the histopathological findings of the endarterectomy specimen.

Results: Of 33 plaques considered on ultrasound to be uniformly or predominantly echolucent (unstable), 27 were found to be largely fatty or haemorrhagic (PPV =82%). Of 17 plaques considered to be predominantly echogenic (stable) on ultrasound, 11 were found to be predominantly fibrotic (PPV = 65%). Correlation between ultrasound irregularity or ulceration and histopathology was poor.

Conclusion: In routine clinical practice, ultrasound can identify with reasonable accuracy, plaques that are predominantly haemorrhagic or fatty, and therefore potentially unstable. This may have future implications in selection of patients for surgery.